Traditionally, computer systems are designed to be able to continuously run a fairly worst-case power load. Design according to such a continuous worst-case power load has never been much of a problem, because traditionally the individual components have had modest operating powers and the computer systems have had large power budgets so that the systems could sustain the load fairly naturally.
As the operating power consumptions of the individual components of computer system creep upwards, the power budgets of the computer systems have become tighter. It is now becoming a challenge to design a computer system to run a continuous worst-case workload while pursuing other high performance goals, such as high computing power, compactness, quietness, better battery performance, etc. For example, portable computer systems, such as laptop computers, have a limited battery output capability; and thus a worst-case workload for a given battery output capability may limit the performance of the system because the worst case workload may rarely occur.